GRCA Issues Flood Warning Update for the Lake Ontario Shoreline

Flood Potential: High

The Ganaraska Region Conservation Authority advises that water levels on Lake Ontario reached a new record peak of 75.92 meters above sea level (masl) earlier this month and have been relatively stable at 75.91 masl for several days now. This is 85 cm above average and will remain well above average for the duration of the summer. Outflows from Lake Ontario are currently set very high by the International Lake Ontario – St. Lawrence River Board (ILOSLRB) in order to try to lower the water level and provide relief to shoreline interests.

Lake Erie continues to rise to new record high levels and is causing high inflows to Lake Ontario. In addition, heavy rainfall on June 20th in the southern part of the basin is contributing to slowing the rate of decline on Lake Ontario. However, with high outflows continuing, the ILOSLRB predicts the water level will decline slowly over the next several months. The rate of decline is largely dependent of rainfall amounts.

The main concern during high lake levels is shoreline erosion and flooding of low-lying shorelines including dynamic beaches and wetlands along the shore. Shortened beaches, waterfront trails and shoreline protections may be damaged by wave action especially during strong winds from the south.

While this Flood Warning is in effect, shorelines may be slippery with unstable banks and bluffs may be actively eroding. Residents are asked to exercise caution around our shorelines and to alert any children in their care of these dangers.

This Flood Warning for the Lake Ontario shoreline was first issued on May 13th and will remain in effect through at least July 25th, 2019. Conservation Authority staff will continue to monitor conditions, and provide updates as necessary. Should you have any questions or wish to report flooding, please contact the following GRCA staff at 905-885-8173.

Mike Smith                                            
Flood Operations Officer                               

Note: A Flood Warning is issued as notice that flooding is imminent or already occurring in specific watercourses or municipalities.